Database examples using Node and MySQL

These examples illustrate the handling of asynchronous database queries using the npm mysql package. In the examples, database tables are created and data is inserted into one of the tables. The data to be inserted is obtained by reading it from an external JSON file.

1-db-naive.js

This example shows how failing to recognize the asynchronous nature of the database queries leads to an error caused by prematurely closing the database connection.

2-db-callback.js

This example correctly closes the connection when all queries have finished. It uses traditional callbacks.

3-db-promise.js

Here, the callbacks are replaced by promises. The functions returning promises are hand-coded.

4-db-async.js

This final version uses async/await and util.promisify().